1. Field of Invention
The present invention relates to a searching technique of the satellites, and more particularly to an electronic device capable of searching satellites and method for searching satellites, thereby finding out the target satellites according to the obtained position information and the obtained time information, and then searching the target satellites based on the found-out target satellites and receiving the satellite signal from the searched target satellite.
2. Related Art
A global position system (GPS) is based on a basic principle of triangulation location of satellites. From the positions of the satellites, the distances between the satellites and the electronic device are measured, thereby obtaining the three-dimensional coordinate value of the position of the electronic device. When the electronic device receives one satellite signal, the electronic device can convert the signal into the distance between its position and the satellite by an internal microprocessor. When the electronic device receives two satellite signals, the electronic device can calculate plane coordinate information. When the electronic device receives a third satellite signal, the electronic device can calculate the coordinate information of its position. Normal electronic devices utilize more than four received satellite signals to determine the position and the height of the electronic device. And if five to six satellite signals or more are received by the GPS continuously, more precise location information may be obtained.
Now considering 32 launched satellites in operation, they are uniformly distributed in six orbit planes. The orbit inclination angle is about 55°. The height of the satellites is about 20,183 kilometers. The period of the satellites is 11 hours and 58 minutes. That is, each satellite orbits the earth twice along the same path. Such a design ensures that the user on the earth can see more than four satellites at any place and any time. When being powered on, the electronic device has to detect whether it can receive the signal from the first satellite, and then sequentially detect whether it can receive the signals from the second satellite to the 32nd satellite. The detecting time for each satellite is about 30 seconds. As such, the user has to wait a very long period of powering on time until all of the 32 satellites have been detected.